Quaternion-based study of angular velocity of the cardiac vector during myocardial ischaemia

PABLO DANIEL CRUCES ; PEDRO D. ARINI

INTERNATIONAL JOURNAL OF CARDIOLOGY

ELSEVIER IRELAND LTD

Lugar: Amsterdam; Año: 2017

0167-5273

Background: Early detection ofacute ischaemia through non-invasive methods remains a challenge in healthresearch. Ischaemic condition caused by a decrease in the blood supply in acardiac region induces hypoxia and metabolic abnormalities that contribute tothe electrical instability of the heart and to the development of slowconduction in damaged tissue. Methods: Herein, a percutaneoustransluminal coronary angiography (PTCA) is considered as a model of supplyischaemia. We use the concept of quaternion to develop a robust method forassessing the angular velocity of cardiac vector in the orthogonal XYZ leads obtained from 92patients undergoing the PTCA procedure. The maxima of angular velocity in bothventricular depolarization and repolarization are combined with traditionallinear velocity indexes in order to obtain a detector of ischaemic episodes(Ischaemia Detector, ID). Results: ID achieves 98%/100% of sensitivity /specificity when differentiating healthy subjects from patients with earlyischaemia. Furthermore, it also shows high accuracy when the comparison is madebetween ischaemic subjects and patients with different non-ischaemic pathologicST-deviations which are known to cause false positives, reaching 95%/98% ofsensitivity/specificity. Moreover, the study of significant reductions(p<0.001) of angular velocity components allows extraction of distinctischaemic common features which are useful for analyzing the dependence ofvectorcardiogram signal on each site of occlusion. The sensitivity of injurylocation reaches values of 88% (RCA), 87% (LAD) and 80% (LCx). Conclusions: Thehigh performance of the proposed method establishes a promising outcome forapplication in computerized assistance in clinical practice.